Pneumatic dispatch-tube



(No Modem E. .11. LBAYGRAPT.

-PNEUMTIC DISPATGHUTUBB.

Patented Oct. 1, 1889.

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i UNITED STATES PATENT EEicE.

EDXVIN D. LEAYCRAFT, F JERSEYCITY, NEV JERSEY.

PNEUMATIC DISPATCH-TUBE.

SPECIFICATION forming part of Letters Patent No. 411,864, dated October 1, 1889.

Application tiled January 18, 1889. Seal No. 296,748. (No model.)

To all whom it' may concern:

Be it known that I, EDWIN D. LEAYCRAET, of Jersey City, in the county of Hudson and State of New Jersey, have invented a certain new and useful Improvement in Pneumatic Dispatch-Tubes, of which the following is a specification.

The improvement relates to the construction of the curved portions. The straight portions may, as heretofore, be tubes having smooth interiors perfectly cylindrical. It has been considered necessary in changing the direction of such tubes to employ curves of so large radius as to frequently seriously weaken the timbers of floors and other parts by cutting into them to accommodate such curves. I have discovered that it is practicable to make curves of small radius by giving a proper form to the cross-section of that portion of the tube. I produce by stamping or other suitable means lengths of sheet met-al curved to the proper radius to extend longitudinally alongthe exterior and interior of the curved portion, the cross-section of the outermost being simply a semicircle, and that of the innermost being a semicircle with a straight portion added on each edge. Each edge of each is flanged. 7When the flanges of the two parte are applied together and properly secured, the structure presents the conditions required, the interiorof the tube having a breadth one way only a little in excess of the diameter of the carrier, and having a breadth the other way sufficiently greater to allow the straight carrier to traverse smoothly around the curve. It will be understood that there are on the inside portion of the curve two extended portions which are plane. The breadth o t the plane metal is proportioned to the curvature of the bend, except that each end of each is narrowed to a point Where the curve is joined to the straight portion.` The breadth of the plane portions should be va ried according to the quickness of the curve and the length of the carrier which is to traverse through th'e tube When in use.

The accompanying drawings form a part of this specification, and represent what I consider the best means of carrying out the invention.

Figure 'l is a side view oi a vertical curve made according to myinvention, with a poi tion of each ot' the straight tubes which it connects. One of the junctions is shown in section. Fig. 2 is a crosssection on the line oc a: in Fie. l. The remaining iigures are cross-sections showing modifications.

Similar letters of reference indicate correspending parts in all the Iigures where they occur.

A and B are straight portions of the tube extending in different directions.

C is the carrier, which is to traverse through The carrier and the straight portions of the tube may be of any ordinary or suitable construction. The curved portions of the tube are cylindrical on their outer and inner sides, but flat on the other two sides. Assuming the curve to be in a vertical plane from a horizontal path downward through a floor, or from a vert-ical path being defiected into a horizontal, the'iiat portions will be on the right and left sides. The dies in which the parts are manufactured are so formed and the pieces which are to be stamped up are so cut by dies or otherwise that the outermost is in cross-section a semicircle with a flange at each edge, and the innermost is a semicircle with an addition of a fia-t part at each edge, and the flange on the edge of that additional dat part. The piece D, with its lia-nge d, applies on the outer side of the curve. The oppositely-conditioncd piece E, with its dat portions F G and its flanges e, applies on the inside of the curve. The ends of these curved portions are circular, and are expanded into sockets H to receive the corresponding ends of the tubes A and B, secured by solden ing or otherwise. The flanges c7j and e are joined by rivets I.

In traversing the straight portions A and B the carrier (E moves in the ordinary man-v ner, with its axis coinciding with the center line of the tube. In traversing the curve the carrier, being straight and rigid, lies always partially transverse to the curved center line of the tube. The form of the cross-section of the curved portion accommodates this position and makes an easy iit in traversing the entire curve. The centrifugal force induces an excess of pressure against the interior of the outer piece D, which varies with the ve locity, but is always sufiiciently great to keep the carrier from pressing with anyconsiderable force against the inner piece E.

Care should be taken in manufacturing and applying together the parts that the interior of the part D be accurately shaped and smoothly finished.

The several parts may be shaped by cutting and stamping in dies. I propose to use soft brass. The shaping may be effected either at a single blow or by a succession of treatments.

Modifications may be made without departing from the principle or sacrificing the advantages of the invention. I can join the fl( nges by other means, as by bolts and nuts, double-seaming, soldering,brazing, &c. It is importantthattheinteriorbetrue andsmooth, A

` d and e and the portions F and G, with their and that the parts form-ing the curve be so connected as to brace and stien each other. I propose in manufacturing in the large Way, where expense is no objection, to Widen the part-s D and E, so that each shall carry a portion of the fiat metal F G. Fig. 3 shows such a modification.

It is practicableto employ interposed fiat portions made separately and joined by flanges. Fig. 4 shows such a modification.

It will be understood that in this modification I interpose between the flanges of the two parts longitudinal plane pieces of sheet metal together.

` Fig. 5 shows such modification.

I claim asmyinvention'- 1. In a pneumatic dispatch-tube, the comb'ination,with cylindrical straight portions,

of a curved portion widened in one direction so as to match to the carrier in traversing if, as herein specified.

2. In a pneumatic dispatch-tube, the flat tened portion D E F G, in combination with the straight' portions A B, and with the joining means H, adapted toserve as herein: specified.

3'. The pieces' D and E, with their' flanges flanges f and g',- and joining means H, arranged as shown, in combination with each other and with the straight lengths of'V cylindrical pipe A and B, as herein specied.

In testimony whereof I have hereuntoset my hand, at New York city, this 16th day of .Ianuary,.l889, in the presence of two subscribing witnesses.

W'itnesses:

CHARLES R. SEARLE, H. A. JoHNsToN'E. 

